HAYDEN 507 HAYES College in 1853, then became professor of geology and mineralogy in the University of Pennsylvania from 1865-1872. The American Geological Expedition which set out in 1855 under Lieut. G. K. Warren to study the upper Missouri was fortunate in having him in its membership to write up and draw the specimens collected. He edited the first eight reports of the "United States Geo- graphical and Geological Surveys of the Territories" and wrote a "Sketch of the Ori- gin and Progress (1877) of that Survey"; also "The Yellowstone National Park and the Mountain Regions of Idaho, Nevada, Colo- rado and Utah" (1877), and "Sun Pictures of the Rocky Mountains" (1870). He was given the degree of LL. D. by the University of Rochester, N. Y., in 1876 and by the Uni- versity of Pennsylvania the year of his death. Century Cyclop, of Names. Smithsonian Contributions to Knowledge, Wash- ington, 1865, vol. xiv. Paleontology of the Upper Missouri, 1864. Hayden, Horace H. (1768-1844). Dr. Hayden was the son of Thomas Hay- den, a lieutenant in the Revolutionary Army, and Abigail Parsons, and the farm upon which one William Hayden settled at Windsor in 1642 is still owned by his descendants. Horace Hayden was born at Windsor, Connecticut, October 13, 1768, and, like his father, became an architect and builder. At the age of four- teen he made two trips to the West Indies as cabin boy abroad a brig. Later, when twenty-one or twenty-two, he again visited these islands, intending to live there, but the unhealthy climate compelled him to return. When sixteen he took up his trade as mechanic and pursued it for several years. His attention was directed to dentistry in 1795 by his needing a dentist and remarking the skill of Mr. John Greenwood, New York. He therefore borrowed books and essays from Greenwood and set to work with energy to master the subject. In 1800 he removed to Baltimore, when an opening presented itself. His knowledge of his new calling was still imperfect and he was without friends and fortune, but he was earnest and ambitious and soon drew practice and instructed students in dentistry in the evenings. It was in conse- quence of his attainments in these and other medical and scientific studies that the hono- rary M. D. was conferred on him by Jeffer- son Medical College in 1837 and by the Uni- versity of Maryland in 1840. During the attack upon Baltimore by the British in 1774 he joined the militia, but medical men being in demand and his surgical skill being rec- ognized he was assigned to duty at the hos- pital as assistant surgeon, where he cared for the wounded as long as his services were required. Although joined by Drs. Chapin and Har- ris in a petition to the authorities of the uni- versity for the foundation of a department of dentistry, he failed to secure his desire and was compelled to found an independent school, the Baltimore College of Dental Sur- gery, which vyas chartered on February 1, 1840, and of which he was president and first professor of the principles of dental science and later professor of dental physiology and pathology, a title he held until his death, four years later. As early as 1817 Dr. Hayden advocated the formation of an association of dental prac- titioners, but only in August, 1840. when a number of prominent American dentists as- sembled in New York City and founded the American Society of Dental Surgeons was this effected. He was chosen its first presi- dent and held this office until death. Dr. Hayden achieved fame also as a ge- ologist, for he collected a valuable cabinet of American minerals, which in 1850 became the basis of the great collection of Roanoke Col- lege, Virginia. The literature was so limited that he was compelled to master the French language that he might have access to the best books on that subject, from which he made many translations. His researches were embodied in a volume of four hundred pages, entitled "Geological Essays" (Baltimore, 1820), said to be the first general work on that subject published in America. He dis- covered a new mineral which was named after him "Haydenite," and he was also a botanist of distinction, writing on silkworm culture, etc. He was a great sportsman. He died at Baltimore, January 26, 1844. On February 23, 1805, he married, at Baltimore, Maria Antoinette Robinson, daughter of Lieut. Daniel Robinson of the United States Reve- nue Service. In 1901 mural tablets were erected at the University of Maryland, and Baltimore College of Dental Surgery. Hay- den's license to practise dentistry is at the former institution. Eugene F. Cordell. Hayes, Isaac Israel (1832-1881). Isaac Israel Hayes, physician and Arctic ex- plorer, was born in Chester County, Pennsyl- vania. His father was Benjamin Hayes and his mother Ann Borton. He graduated in medicine at the University of Pennsylvania
